1. Field of Invention
This invention pertains to floor tiling, in general, and to tactile floor tiling, in particular. Tactile floorings have an uneven surface so that they can provide information about the surroundings to those walking on them, e.g., blind and partially-sighted people.
2. Description of the Related Art
There is an international standard for the designs and uses of tactile tiling, for example, tiles with ‘blisters’ arranged on a square pattern are used on pavements at the edges of pedestrian crossings, tiles with a triangular pattern are used near the edges of railway platforms, and tiles with regularly spaced parallel ridges are used at the tops and bottoms of stairs. In this context, the ‘blisters’ are about 25 mm in diameter, about 5 mm high, and spaced 67 mm apart. Such tiling is highly beneficial to blind people because the blisters can be detected by both a stick sweeping the ground in front of them and through the soles of their shoes. Tactile tiles may be provided in a contrasting color to that of the rest of the flooring so that sighted caregivers for blind persons and partially sighted people may be further warned of the impending hazard.
Tactile tiling is used both outside, e.g., in the street and public spaces, and inside, e.g., in public access areas, shopping malls, and locations particularly frequented by blind people. For outside use, the tiles are often cast from concrete or similar materials, but for inside use, they are usually made from polymeric materials, sometimes incorporating a degree of cushioning.
FIG. 1 shows a current design of polymeric tile and some problems associated with it. Tile 1 consists of regularly spaced blisters 2 on a substrate 3. The upper face has a hard-wearing surface 4. Because of the shape and pattern of the blisters 2, tile 1 has to be cast upside down, i.e., with the blisters at the bottom of the mold, and so, lower surface 5 is the top surface in the mold. The mixture from which the tile is cast contains resin, hardener, and a filler, such as sand or grit particles.
In the manufacturing process. it is normal to fill the mold and then vibrate it to release trapped air bubbles and settle the mixture fully down into the mold. This vibrating process also causes the filler particles to settle in the resin mixture and leave a smooth surface at the top of the mold. Thus, after polymerization and removal from the mold, this smooth surface becomes lower surface 5 of tile 1. When the flooring is fitted, it is normal to bond tiles 1 adhesively to a wood or concrete foundation. A smooth surface 5 is not ideal for adhesive bonding. It is possible to roughen surface 5, e.g., with sandpaper, but this is not really practicable when working to deadlines. The result is that, in use, tiles frequently become wholly, or partly, unbonded and detached from the foundation.
Another problem that arises, occurs because the polymerization process continues after the tiles have been removed from the mold. If tiles 1 are not stored perfectly flat, e.g., they are placed on a slightly uneven surface or, perhaps, overlapping the edge of a pallet, it is possible that a ‘kink’, resulting in a ‘permanent set’, may occur. This is illustrated as displacement 6 in FIG. 1. Though the tile 1 may be ‘bent straight’ by the person laying the floor and then adhesively bonded to the substrate, the distortion 6 remains as an internal tensile stress. It is known that adhesive bonds are weak in tension and, especially when the adhesive is bonded to a smooth surface 5, failure of the bond is a high probability. Adhesive failure, whether due to the smooth surface 5, or exacerbated by a kink 6, is a common problem with the fixing of this form of tile.
There is thus a need for a form of tiling with a hard wearing surface and cushioned substrate, which can be bonded firmly to the flooring foundation and remains firmly bonded for the lifetime of the tile.